A mechanical testing machine is essential in the evaluation of biomaterials. Our present Instron TTM Universal Testing Machine was purchased in 1959 and it has been the backbone of our mechanical testing of biomaterials. This model was last produced in 1974 and we have been advised by the Instron Corporation (see Appendix A) that a number of parts are no longer available (e.g. amplidyne, clutch, vacuum tubes, etc.), and repairs may not be possible. State-of-the-art mechanical testers are servohydraulicly driven and have digital output and are computer controlled, plus have biaxial and uniaxial loading. A mechanical tester of this type is essential in evaluating the mechanical properties of composites, substitutes for dentin, maxillofacial materials, ceramics, chewing studies, and strengths of attachment of cements and implants to bone. The ability of such an instrument to test materials under uniaxial and biaxial loading is essential in the future evaluation and development of many and especially implant materials. The Instron we are proposing to purchase will have adequate loading and displacement ranges with computer controlled servohydraulic biaxial loading and special clamping fixtures for brittle materials (ceramics). We also propose purchasing an x-y recorder and an HP 7090A computer to complete the package (note: Instron does not supply these two items).